Mechanical fire suppression systems are pervasive in restaurants and have been used to protect kitchen and cooking appliances from the threat of a fire. Typically, these mechanical fire suppression systems work on a simple principle: a tensioned cable and a group of mechanical fuses are installed in the hood above the cooking surfaces and are connected to a trigger mechanism outside the hood area. The mechanical fuses are unaffected by normal operating temperatures or low heat levels. However, when enough heat is generated by a fire, any fuse exposed to the excessive heat breaks and releases tension on the cable thereby activating the trigger mechanism. The activation of the trigger mechanism causes a cascading series of events, including the activation of a pressurized cartridge, the dispersion of a chemical suppression agent on the cooking surfaces, shutdown of the gas or electricity powering the cooking appliances, changes in air handling equipment, and potentially the activation of visual and audible alarms.
Due to the mechanical nature of these traditional fire suppression systems, there are some very rigorous inspection and maintenance requirements that must be routinely performed. One of the primary reasons for these regular inspection and maintenance requirements is that these systems are often exposed to a large amount of grease and oil, which can build up and detrimentally affect the operation of the fire suppression system. As a result, failure to maintain the system properly will most likely lead to issues, such as a false discharge (mechanical fuses eventually fail due to the excessive number of hot and cold cycles they are put through), or no discharge as the fuses or other parts of the cable are encased in hardened grease. Consequently, these systems need to be cleaned, inspected, and serviced regularly (e.g., on a three to six month cycle, depending on the environment).
While regular inspection and maintenance is essential for proper operation of the fire suppression systems, there are many pitfalls in the maintenance regime that could result in improper operation of the fire suppression system. For example, as part of the maintenance of a hood, technicians typically disable the detection line and remove pressurized cartridges to allow the technician to properly inspect and work on the system with no chance of a false discharge. Unfortunately, the cartridge may not be reinstalled, the detection line may not be put back on line, or both. Left in any one of these states, the fire suppression system provides no suppression protection and is useless.